I have a 140 width 16 inch tire on the rear of my 75. It's very tight.
On the 18 inch wheel a 120 tire will fit.
Some tires that are 130, 120, whatever wide can vary from different manufactures.
Some are a bit wider for a given size, some narrower.
When I got my bike it had an 18 inch wheel with a 120 wide Dunlop tire on the back, I don't recall the model of tire. When I went to get it replaced with a Kenda, a 120 was to wide, I had to use a 110.
When you get new tires, if you can compare the new to old for width wouldn't hurt any thing.
The people on here can give you more insight into what fits. I have only changed the tires once on both ends of the bike with the stock wheels, and just once with my 16 rear wheel.